How do we determine what is a prudent price for a vacation?
Honestly, I think you just KNOW! When you look at something you can just feel yourself deciding either that it's worth it or it isn't.
We take all the factors into consideration (duration, distance, location, activities, transportation, desirability, etc) and decide what we think would be a fair price for the experience and then judge the price tag accordingly.
I approach vacation planning one of two ways...
Either I set a budget and find a trip to match
OR
I pull a vacation from the bucket list and price it out. If it seems too expensive, I do tons of research trying to preserve the experience whilst making concessions that bring the cost down. (ie switching cruise lines, driving versus flying, finding less expensive accommodations a little further afield from the sights, etc).
For example, our next vacation will be a Mediterranean cruise. This is at the top of our family's bucket list and we've been looking forward to it for years. The kids are finally old enough to appreciate and keep up with the itinerary DH and I want to follow. Because it's so important to us, we are prepared to pay more for this particular trip than we do for most of our other vacations. It's value is increased simply because we want it so bad.
Even so, we ARE looking for ways to bring the cost down. Unless we get a ridiculously great last minute deal...we will not (gulp) be cruising with Disney. I have spent hours researching the travel options. Some discount airlines only fly on certain days and to certain European cities. I have found that quite a lot of money can be saved by taking advantage of these adjustments.
We've also really cut back on our souvenier money in recent years. A small token from our travels doesn't add to our memories of the experience any less than a big expensive one does.
Good luck with your trip. I hope you can fiind a version of what you want with a price you can be happy with!!